Amide Amine Research Articles

Long-circulation zwitterionic dendrimer nanodrugs for phototherapy of tumors

The development of stealth and effective antitumor nanodrugs has been drawing great attention. Herein, generation five poly(amide amine) dendrimer (G5 PAMAM) was modified by zwitterionic material carboxybetaine methacrylamide (CBMAA) on its surface to prepare zwitterionic dendrimer (G5-CBMAAn). The results showed that G5-CBMAA30 had the longest blood circulation time due to its thickest zwitterionic layer, and its residual rate after injection into mice at 2 and 12 h was as high as 47.22 % and 14.37 %, respectively. Nanodrug G5-CBMAA30-ICG was prepared by containing indocyanine green (ICG) in the cavity of G5-CBMAA30. G5-CBMAA30-ICG had better tumor targeting ability and antitumor effect than free ICG in mice after laser irradiation, and the tumor inhibition rate was 96.6 % after 14 days’ treatment. The prepared G5-CBMAA30-ICG has great potential applications in the field of antitumor by phototherapy.

Lithium, Magnesium, and Zinc Centers N,N′-Chelated by an Amine–Amide Hybrid Ligand

The synthesis and structure of lithium, magnesium, and zinc complexes N,N'-chelated by a hybrid amine-amido ligand ([2-(Me2NCH2)C6H4NR]-, abbreviated as LNR, where R = H, SiMe3, or Bn) are reported. The reaction of the least sterically demanding LNH with various magnesium sources gives the hexameric imide [LNMg]6 (4) by the elimination of n-butane from LNHMgnBu (2) or by the reaction of LNHLi (1) with MeMgBr. [LNH]2Mg (3) is obtained through the addition of 0.5 equiv of nBu2Mg or Mg[N(SiMe3)2]2 to LNH2 and with 1 equiv of nBu2Mg reacting to 2. Both LNHMgN(SiMe3)2 (6) and isostructural LNHZnN(SiMe3)2 (16) have been prepared using two different approaches: monodeprotonation of LNH2 by Zn/Mg[N(SiMe3)2]2 in a 1:1 ratio or ligand substitution of 2 or LNHZnEt (12) by 0.5 equiv of Sn[N(SiMe3)2]2. The reactions of 2 or 3 with 1 provide the heterotrimetallic complex [LNH]4Li2Mg (5). Benzyl- or trimethylsilyl-substituted anilines [LN(SiMe3)H (7) and LN(Bn)H (8)] with 0.5 equiv of nBu2Mg allow the formation of homoleptic bis(amides) of the [LN(R)]2Mg type (10 and 11). Nevertheless, only the silylated secondary amine 7 is able to provide the heteroleptic n-butylmagnesium amide LN(SiMe3)MgnBu (9) upon reaction with an equimolar amount of nBu2Mg. Similarly, 12, [LNH]2Zn (13), LN(R)ZnEt (17 and 18), and [LN(R)]2Zn [R = SiMe3 (19) and Bn (20)] were prepared by the monodeprotonation of LNH2 or LN(R)H using Et2Zn in the corresponding stoichiometric ratio. LNHZnI was prepared by the nucleophilic substitution of an ethyl chain in 12 by molecular iodine. A heterometallic complex, [LNH]4Li2Zn (14), analogous to 5 was prepared from 12 or 13 with 1 or 2 equiv of 1, respectively.

Single-Molecular Mn(I)-Complex-Catalyzed Tandem Double Dehydrogenation Cross-Coupling of (Amino)Alcohols under Solventless Conditions with the Liberation of H2 and H2O

Sustainable chemical production requires fundamentally new types of catalysts and catalytic technologies. The development of coherent and robust catalytic systems based on earth-abundant transition metals is essential but extremely challenging. Herein, we report the first report on a single Mn(I)-PNP catalyzed tandem C–C and C–N bond formation via double dehydrogenative coupling of amino alcohols with primary alcohols. The current method covers a wide range of substrates, including aryl, aliphatic, acyclic, and cyclic primary alcohols, as well as amino alcohols, to provide diverse N-heterocyclic compounds (pyridine and quinoline derivatives) in good to excellent yields (50 examples). The reaction proceeds under benign, solventless conditions with the liberation of molecular hydrogen and water as the only byproducts. Various control and labeling experiments and kinetic, nuclear magnetic resonance, and mechanistic studies suggest that the reaction operates via the acceptorless double dehydrogenative coupling pathway, selectively assimilating to provide desired N-heterocycles. Several selective bond activation/formation reactions occur sequentially via amine–amide metal–ligand cooperation.

Hyaluronidase enzyme conjugated polyamidoamine dendrimer: An efficient and stable nanobiocatalyst for enzymatic degradation of hyaluronic acid

In this work hyper-branched poly (amide amine) (PAMAM) nanoparticles were conjugated with hyaluronidase (Hyal) to produce a robust nano-biocatalyst for hyaluronic acid (HA) degradation. The success enzyme attachment process was confirmed by Fourier transform infrared (FTIR), transmission electron microscopy (TEM), dynamic light scattering (DLS), and UV–Vis. The influence of pH, temperature, and inhibitor on the enzymatic activity of hyaluronidase was also investigated. The optimum pH, temperature and storage time of Hyal-PAMAM nanocomplex were higher than free enzyme. Also, ascorbic acid showed more inhibitory effect on free enzyme, the IC50 values were determined to be around 55 ± 0.7 and 70 ± 0.3 mM for free Hyal and Hyal-PAMAM nanocomplex, respectively. Based on the greater υmax and lower Km, the Hyal-PAMAM showed a better catalytic efficiency for HA degradation. Moreover, the in silico screening of PAMAM/Hyal interactions further confirmed the experimental results. The novel strategy for combining Hyal and PAMAM dendrimer can hold great promise for applications in biomedical, sensing, and industrial catalysis.

Distinct rhodamine B derivatives exhibiting dual effect of anticancer activity and fluorescence property

Design and application of novel Rhodamine B amide derivatives achieved especially with simple secondary amines, and furthermore exhibiting fluorescence property and anticancer activity is not reported elsewhere. Further functionalization of rhodamine B at the carboxylic acid group with selected secondary amines generated amides, avoiding cyclization and simultaneously sustaining fluorescence. Currently, we have designed and developed three well defined novel rhodamine B amide derivatives by reacting rhodamine B (RHB) with thiomorpholine, bis-(2-chloroethyl) amine and morpholine (the side chains of several anticancer drugs) via rhodamine B acid chloride which resulted in fluorophores namely rhodamine B thiomorpholine amide (1), rhodamine B bis(2-chloroethyl)amine amide (2) and rhodamine B morpholine amide (3). All the three RHB amides were thoroughly characterized using analytical techniques like FT-IR, Mass, 1H NMR, 13C NMR spectroscopy and HPLC. Obtained compounds displayed molecular material attributes as well as anticancer activity. The wavelength of maximum absorption and emission of solutions occurred at ~560 nm and ~583 nm. Quantum yields (Φf = 0.40) and average fluorescence decay (~1.60 ns) of amides was comparable to RHB (1.72 ns). Optical bandgap of solids revealed semiconducting property (~ 2.9 eV). Acquired rhodamine B amides were found to be insensitive over a wide range of pH i.e. from 2 to 10 suggesting their plausible utility in biological labeling, moreover, showed potential anticancer activity against B16F10 (murine melanoma cells), MDA-MB231 (human breast cancer cells), A549 (human lung cancer cells) while they displayed less toxicity to normal HEK 293 (human embryonic kidney) cells. Interestingly, the cellular uptake study manifested that more quantity of the compound were taken up by the cancer cells compared to normal cells which indicate that these amides might become potential candidates to be developed as theranostic agents.

Amide-Amine Replacement in Indole-2-carboxamides Yields Potent Mycobactericidal Agents with Improved Water Solubility.

Indolecarboxamides are potent but poorly soluble mycobactericidal agents. Here we found that modifying the incipient scaffold by amide-amine substitution and replacing the indole ring with benzothiophene or benzoselenophene led to striking (10-20-fold) improvements in solubility. Potent activity could be achieved without the carboxamide linker but not in the absence of the indole ring. The indolylmethylamine, N-cyclooctyl-6-trifluoromethylindol-2-ylmethylamine (33, MIC90Mtb 0.13 μM, MBC99.9Mtb 0.63 μM), exemplifies a promising member that is more soluble and equipotent to its carboxamide equivalent. It is also an inhibitor of the mycolate transporter MmpL3, a property shared by the methylamines of benzothiophene and benzoselenophene.

Ruthenium-Catalyzed Direct Cross-Coupling of Secondary Alcohols to β-Disubstituted Ketones

The β-disubstituted ketone functionality is prevalent in biologically active compounds and in pharmaceuticals. A ruthenium-catalyzed direct synthesis of β-disubstituted ketones by cross-coupling of two different secondary alcohols is reported. This new protocol was applied to the synthesis of variety of β-disubstituted ketones from various cyclic, acyclic, symmetrical, and unsymmetrical secondary alcohols. An amine–amide metal–ligand cooperation in a Ru catalyst facilitates the activation and formation of covalent bonds in selective sequences to provide the products. Kinetic and deuterium-labeling experiments suggested that aliphatic alcohols oxidize faster than benzylic secondary alcohols. A plausible mechanism is proposed on the basis of mechanistic and kinetic studies. Water and H2 are the only byproducts from this selective cross-coupling of secondary alcohols.1 Introduction2 Catalytic Self- or Cross-Coupling of Alcohols and Selectivity Challenges3 Recent Developments in the Synthesis of β-Disubstituted Ketones4 Scope of Ruthenium-Catalyzed Cross-Couplings of Secondary Alcohols5 Mechanistic Studies and Proposed Mechanism6 Conclusion

Nuclear localization signal peptide enhances transfection efficiency and decreases cytotoxicity of poly(agmatine/N,N'-cystamine-bis-acrylamide)/pDNA complexes.

At present, nonviral gene vectors develop rapidly, especially cationic polymers. A series of bioreducible poly(amide amine) (PAA) polymers containing guanidino groups have been synthesized by our research team. These novel polymer vectors demonstrated significantly higher transfection efficiency and lower cytotoxicity than polyethylenimine (PEI)-25kDa. However, compared with viral gene vectors, relatively low transfection efficiency, and high cytotoxicity are still critical problems confronting these polymers. In this study, poly(agmatine/N,N'-cystamine-bis-acrylamide) p(AGM-CBA) was selected as a model polymer, nuclear localization signal (NLS) peptide PV7 (PKKKRKV) with good biocompatibility and nuclear localization effect was introduced to investigate its impact on transfection efficiency and cytotoxicity. NLS peptide-mediated in vitro transfection was performed in NIH 3T3 cells by directly incorporating NLS peptide with the complexes of p(AGM-CBA)/pDNA. Meanwhile, the transfection efficiency and cytotoxicity of these complexes were evaluated. The results showed that the transfection efficiency could be increased by 5.7 times under the appropriate proportion, and the cytotoxicity brought by the polymer vector could be significantly reduced.

Minus F and Square F-Indices and Their Polynomials of Certain Dendrimers

We introduce the minus F-index and square F-index of a graph. In this study, we determine the minus F-index, square F-index and their polynomials of porphyrin dendrimer, propyl ether imine dendrimer, zinc porphyrin dendrimer and poly ethylene amide amine dendrimer.

Autofluorescent Hyperbranched Poly(amide amine) as Effective Fluorescent Probe for Label-free Detection of Copper(II) Ions.

A label-free fluorescent probe based on autofluorescent hyperbranched poly(amide amine) (HPAMAM) for copper ions was designed. HPAMAM is a cationic polymer containing many amino groups, which could bind Cu2+ ions to form cupric amine complexes, leading to a selective quenching of the fluorescence intensity of HPAMAM via inner filter effect. The fluorescence intensity of HPAMAM decreased with increasing concentration of Cu2+ ions and the linear response ranged from 0.05 to 25 μM (R2 = 0.995), with the corresponding detection limit (3σ/k) of 17.15 nM. The HPAMAM fluorescent probe provided a simple, rapid, selective and sensitive fluorometric method for detecting Cu2+ ions, which could be also applied for detection of Cu2+ ions in real water samples.

Low systemic toxicity nanocarriers fabricated from heparin-mPEG and PAMAM dendrimers for controlled drug release

In this report, poly(amide amine) (PAMAM) dendrimer and Heparin-grafted-monomethoxy polyethylene glycol (HEP-mPEG) were synthesized and characterized. In aqueous solution, the generation 4 PAMAM dendrimers (G4.0-PAMAM) existed as nanoparticles with particle size of 5.63nm. However, after electrostatic complexation with HEP-mPEG to form a core@shell structure G4.0-PAMAM@HEP-mPEG, the size of nanoparticles was significantly increased (73.82nm). The G4.0-PAMAM@HEP-mPEG nanoparticles showed their ability to effectively encapsulate doxorubicin (DOX) for prolonged and controlled release. The cytocompatibility of G4.0-PAMAM@HEP-mPEG nanocarriers was significantly increased compared with its parentally G4.0-PAMAM dendrimer in both mouse fibroblast NIH3T3 and the human tumor HeLa cell lines. DOX was effectively encapsulated into G4.0-PAMAM@HEP-mPEG nanoparticles to form DOX-loaded nanocarriers (DOX/G4.0-PAMAM@HEP-mPEG) with high loading efficiency (73.2%). The release of DOX from DOX/G4.0-PAMAM@HEP-mPEG nanocarriers was controlled and prolonged up to 96h compared with less than 24h from their parentally G4.0-PAMAM nanocarriers. Importantly, the released DOX retained its bioactivity by inhibiting the proliferation of monolayer-cultured cancer HeLa cells with the same degree of fresh DOX. This prepared G4.0-PAMAM@HEP-mPEG nanocarrier can be a potential candidate for drug delivery systems with high loading capacity and low systemic toxicity in cancer therapy.

Synthesis, characterization, and surface properties of amide amine oxides based on natural vegetable oil

ABSTRACTTwo types of novel amine oxide surfactants, castor oil amide amine oxide and cottonseed oil amide amine oxide, have been successfully synthesized via a two-step synthetic route with mild reaction conditions, the chemical structures of which were confirmed by mass spectra (MS) and FTIR spectra. Their surface activities have been measured. The results show that these synthesized amide amine oxide surfactants reduced the surface tension of water to a minimum value of approximately 32.48 mN/m at a concentration of 5.06 × 10−5 mol/L. It was also found that these novel amide amine oxide surfactants exhibited strong emulsifying power.

Communication—The Effects of the Type of Hyperbranched Polymers on the Interfacial Properties of Carbon Fiber Composites

The effects of different hyperbranched polymers on the mechanical properties of carbon fiber (CF) composites have been investigated. The characterization results confirmed that both hyperbranched polyglycerol (HPG) and hyperbranched poly(amide amine) (HPAMAM) were successfully grafted onto carbon fiber surface. The hyperbranched polymers could introduce sufficient functional groups, especially chair conformation, and covalent bond between fiber and epoxy matrix, leading to the great enhancement of mechanical properties of the composites. In addition, after HPAMAM containing chair conformations grafted, the IFSS afforded a highest increase of 100.18%, higher than that of the carbon fiber grafted with HPG composites (86.42%).

ChemInform Abstract: The Development of New Amine—Amide Ligands for Application in Cu(II)‐Catalyzed Enantioselective Henry Reactions.

AbstractCombined with Cu(II) acetate, novel BINOL‐derived chiral tertiary amine ligands are developed as catalysts for the asymmetric Henry reaction of aromatic, heteroaromatic, and aliphatic aldehyde substrates.

The development of new amine–amide ligands for application in Cu(II)-catalyzed enantioselective Henry reactions

A new type of chiral tertiary amine ligand was designed and derived from l-proline and (R)-BINOL. These new chiral ligands chelated with Cu(II) showed highly catalytic efficiency in enantioselective Henry reactions. Excellent yields (up to 99%) and high enantioselectivities (up to 96% ee) were achieved for aromatic, hetero-aromatic and aliphatic aldehyde substrates, without an additional base additive or the need for air or moisture exclusion.

Concentration of manganese tailings via reverse flotation in an acid médium

Beneficiation of manganese ores has been conducted around the world by circuits composed basically of crushing, screening and spiral classifier. Therefore, solely the coarse size fractions (and commonly the richest) are actually recovered: "lump" (-75+9mm) and "sinter feed" (-9+0.15mm). In the industrial plant which processes the ore from the Azul Mine-PA, the overflow of the spiral classifier (- 0.15mm) is disposed of in a tailings dam because it bears a low Mn content (<10%) and high kaolinite content (70%). This paper reports the findings of a process development conducted on laboratory scale with the aim of concentrating Mn-bearing minerals from the tailings of the Azul Mine-PA (7% of Mn and 70% of kaolinite). The process is composed of desliming (-10µm), followed by reverse cationic flotation of kaolinite (rougher, scavenger) at pH~5. Results indicate that the reverse cationic flotation in the acid medium, when utilizing amide amine as collector and in the presence of a silicate activator and a dispersing agent could be a possible route for the concentration of tailings that had previously been deslimed at 10µm. The results yielded a mass recovery of 18%, a metallurgical recovery of 50% and a 32% Mn concentrate which may be mixed with current high grade products, increasing the overall recovery of the plant.

Rhodium(III) extraction from aged hydrochloric acid solutions with triacylated pentaethylenehexamine trihydrochloride

Rhodium(III) extraction from aged hydrochloric acid solutions with triacylated pentaethylenehexamine trihydrochloride was studied. It was shown that the studied reagent is equal in extraction ability to the known amide–amine derivative, N-n-hexyl-bis-(N-methyl-N-n-octylethylamid)amine. The composition of extracted compounds was established with the use of elemental analysis, electronic, IR, and NMR spectroscopy.

Cytocompatibility of amine functionalized carbon nanoparticles grafted on polyethylene

Five types of amide–amine Carbon Nano-Particles (CNPs) were prepared by functionalization of CNPs and characterized by several analytical methods. The successful grafting of amines on CNPs was verified by X-ray photoelectron spectroscopy (XPS), organic elemental analysis and electrokinetic analysis. The size and morphology of CNPs were determined from transmission electron microscopy. The surface area and porosity of CNPs were examined by adsorption and desorption isotherms. Differential scanning calorimetry was used to investigate thermal stability of CNPs. The amount of bonded amine depends on its dimensionality arrangement. Surface area and pore volumes of CNPs decrease several times after individual amino-compound grafting. Selected types of functionalized CNPs were grafted onto a plasma activated surface of HDPE. The successful grafting of CNPs on the polymer surface was verified by XPS. Wettability was determined by contact angle measurements. Surface morphology and roughness were studied by atomic force microscopy. A dramatic decrease of contact angle and surface morphology was observed on CNP grafted polymer surface. Cytocompatibility of modified surfaces was studied in vitro, by determination of adhesion, proliferation and viability of vascular smooth muscle cells (VSMCs). Grafting of CNPs onto the polymer surface has a positive effect on the adhesion, proliferation and viability of VSMCs.

One-Pot Palladium-Catalyzed Ligand- and Metal-Oxidant-Free Aerobic Oxidative Isocyanide Insertion Leading to 2-Amino-substituted-4(3H)-quinazolinones

An efficient, ligand- and metal-oxidant-free, one-pot, cascade aerobic oxidative, palladium-catalyzed, multicomponent reaction has been developed through isocyanide insertion of less active secondary amide and aromatic amine, which leads to 2-amino-substituted-4(3H)-quinazolinones. This approach proves to be one of the simplest methods for the synthesis of this class of valuable bioactive heterocyclic scaffolds.

Microwave Synthesis and Characterization of a Silver–Poly (Amide Amine) Dendrimer Nanocomposite with Application as a Hydrogen Peroxide Sensor

A novel procedure to fabricate a nonenzymatic hydrogen peroxide sensor was developed based on a silver-poly (amide amine) dendrimer nanocomposite synthesized by a microwave procedure. The formation of silver nanoparticles functionalized with the poly (amide amine) dendrimer was confirmed by ultraviolet visible spectroscopy, high resolution transmission electron microscopy, and energy-dispersive X-ray spectroscopy. The electroanalytical properties of a glassy carbon electrode modified with the silver-poly (amide amine) dendrimer nanocomposite were evaluated by the determination of hydrogen peroxide. The electrochemical sensor exhibited rapid response and high sensitivity to hydrogen peroxide with a linear dynamic range from 1.0 × 10–5 to 3.7 × 10–3 molar (r = 0.998) and a limit of detection of 5.06 micromolar. The sensitivity was 30.24 microampere · per millilmolar per square centimeter and the response time was three seconds at a working potential of −0.35 volt. In addition, the sensor was unaffected by the presence of ascorbic acid, citric acid, and oxalic acid. These results indicate that the silver-poly (amide amine) dendrimer nanocomposite based sensor has application for the determination of hydrogen peroxide.